Pneumatic Tire

ABSTRACT

A pneumatic tire is provided including a plurality of protrusions and a plurality of recesses of at least one tire side portion. A region including the recesses is provided in the outermost side in a tire radial direction. The protrusions are formed as convexities having a longitudinal shape in a predetermined direction. A region including the protrusions is provided inward in the tire radial direction of the region including the recesses.

RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 13/631,121filed on Sep. 28, 2012, which claims priority to Japan PatentApplication Serial No. 2011-213011 filed on Sep. 28, 2011.

BACKGROUND

Technical Field

The present technology relates to a pneumatic tire and particularlyrelates to a pneumatic tire by which air flow around a tire can beimproved.

Related Art

Japanese Unexamined Patent Application Publication No. 2010-260376Adescribes a conventional pneumatic tire including both a plurality ofconcave portions (recesses) and a plurality of convex portions(protrusions) throughout a tire circumferential direction and a tireradial direction in a predetermined region of a tire outer side surfacefor the purposes of effectively reducing air resistance around the tireand improving the fuel economy of a vehicle on which the tire ismounted.

With the pneumatic tire described in Japanese Unexamined PatentApplication Publication No. 2010-260376A, it is recited that turbulentflow (agitation of air) around the tire is generated by the concaveportions when the vehicle is traveling, and an increase in the effectsof generating turbulent air (agitation effects) is sought by the convexportions. That is, the concave portions are described as portions thatcause turbulent flow or agitate the air, and the convex portions aredescribed as portions that promote the turbulent flow or agitation ofthe air.

In cases where the tire is mounted on a vehicle with a fender, the airflow around the tire is not uniform and air resistance is negativelyaffected. Therefore, there are demands to further improve the air flowaround the tire in order to enhance fuel economy.

SUMMARY

The present technology provides a pneumatic tire by which air flowaround the tire can be further improved. A pneumatic tire of the presenttechnology includes a plurality of recesses and a plurality ofprotrusions of at least one tire side portion. In such a pneumatic tire,a region including the recesses is provided in an outermost side in atire radial direction, the protrusions are formed as longitudinalconvexities in a predetermined direction, and a region including theprotrusions is formed inward in the tire radial direction of the regionincluding the recesses.

According to this pneumatic tire, when a vehicle on which the pneumatictire is mounted is traveling, the air can be made turbulent by therecesses by providing the region including the recesses in an outer sidein the tire radial direction of the tire side portion that is prone toreceiving air resistance and where rotation speed is relatively fast. Asa result, a turbulent flow boundary layer is generated in the regionincluding the recesses and the expansion of passing air is suppressed.That is, separation of the flow of air from a shoulder portion (alsoreferred to as a buttress portion), which is a portion on the outer sidein the tire width direction of the tread portion and that is inclinedtoward the inner side in the tire radial direction, is suppressed. As aresult, a point where the flow of air separates can be offset backwardand, therefore, the air resistance of the entire tire is reduced andfuel economy is enhanced. On the other hand, when a vehicle on which thepneumatic tire is mounted is traveling, the flow of air, for whichseparation has been suppressed by the recesses, is made turbulent by theprotrusions by providing the region including the protrusions on theinner side in the tire radial direction of the tire side portion, wherethe rotation speed is relatively slow. Therefore, the turbulent flowboundary layer is generated in the region including the protrusions andthe expansion of passing air is further suppressed and, as a result, theair resistance of the vehicle is reduced and the fuel economy isenhanced. Moreover, because the protrusions rectify the flow of air forwhich separation was suppressed by the recesses, and expel the flow ofair to the back of the tire, the air resistance of the vehicle can befurther reduced. Particularly, with a vehicle in which the pneumatictire is disposed within the fender, air is expelled to the back of thefender by the protrusions and, therefore, the air resistance of thevehicle is further reduced. As described above, with this pneumatictire, the air flow around each tire can be further improved due to therecesses in the outer side in the tire radial direction and theprotrusions on the inner side in the tire radial direction of the tireside portion.

Additionally, with the pneumatic tire of the present technology, in astate when assembled on a regular rim and inflated to an inner pressureof 5% of a regular inner pressure, the region including the recesses isa range of at least 10% of a tire cross-sectional height outward from aground contact edge of a tread portion in the tire width direction andinward from the ground contact edge in the tire radial direction; andthe region including the protrusions is a range of at least 10% of thetire cross-sectional height outward from a rim check line in the tireradial direction.

The range of at least 10% of a tire cross-sectional height outward fromthe ground contact edge of the tread portion in the tire widthdirection, and inward from the ground contact edge in the tire radialdirection is a portion in the tire side portion that is most prone toreceiving the air resistance and where the rotation speed is fastest. Byconfiguring this range to be the region including the recesses, aprominent effect of reducing the air resistance of the entire tire canbe obtained and the fuel economy can be further enhanced. On the otherhand, the range of at least 10% of the tire cross-sectional heightoutward from the rim check line in the tire radial direction is aportion in the tire side portion where the rotation speed is slowest. Byconfiguring this range to be the region including the protrusions, theflow of air for which separation was suppressed by the recesses can bemade more turbulent, a prominent effect of reducing the air resistanceof the vehicle can be obtained, and the fuel economy can be furtherenhanced.

With the pneumatic tire of the present technology, a longitudinaldirection dimension of the protrusions is not less than 5 mm.

If the longitudinal direction dimension of the protrusions is less than5 mm, it will be difficult to obtain the effect of making the airturbulent by the protrusions. Therefore, configuring the longitudinaldirection dimension of the protrusions to be not less than 5 mm makes itpossible to make the air turbulent and obtain a prominent effect ofreducing the air resistance of the vehicle.

With the pneumatic tire of the present technology, a protruding heightof the protrusions is not less than 0.5 mm and not more than 10.0 mm.

If the height of the protrusions is less than 0.5 mm, a range of theprotrusions that contacts the air will be small and, as a result, itwill be difficult to make the flow of air turbulent and the effect ofreducing the air resistance of the vehicle will decline. Additionally,if the height of the protrusions exceeds 10.0 mm, the range of theprotrusions that contacts the air will be large and, as a result, theflow of air at the back of the protrusions will tend to expand and theeffect of reducing the air resistance of the vehicle will decline.According to this pneumatic tire, the protrusions appropriately contactthe air and, therefore, the flow of air is made turbulent and theexpansion of the air at the back of the protrusions is reduced. As aresult, a prominent effect of reducing the air resistance of the vehiclecan be obtained.

With the pneumatic tire of the present technology, a longitudinaldirection of the protrusions is disposed along the tire radialdirection.

According to this pneumatic tire, the protrusions formed with alongitudinal shape in the tire radial direction have many faces facingthe air passing around the tire and make the air more turbulent.Therefore, a prominent effect of reducing the air resistance of thevehicle can be obtained.

With the pneumatic tire of the present technology, a cross-sectionalshape of the protrusions has a peak and progressively expands toward abottom surface side.

According to this pneumatic tire, the cross-sectional shape of theprotrusions that is orthogonal to the longitudinal direction resembles atriangle shape and, thereby, the volume of the protrusions is lesscompared to that of a rectangular cross-section or the like. As aresult, the rubber volume of the protrusions is reduced and an increasein tire weight is suppressed and, therefore, the fuel economy can befurther enhanced.

With the pneumatic tire of the present technology, a cross-sectionalshape of the protrusions includes at least one arc.

According to this pneumatic tire, for example, the cross-sectional shapeof the protrusions may be formed so as to expand using the arc or, thecross-sectional shape of the protrusions may be formed so that the arcis recessed. As a result, because the volume of the protrusions is lesscompared to that of a rectangular cross-section or the like, the rubbervolume of the protrusions is reduced and an increase in tire weight issuppressed and, therefore, the fuel economy can be further enhanced.

With the pneumatic tire of the present technology, a depth of therecesses is not less than 0.5 mm and not more than 5.0 mm.

If the depth of the recesses is less than 0.5 mm, a range where an innersurface of the recesses contacts the air will be small and, as a result,it will be difficult to make the flow of air turbulent. Additionally, ifthe depth of the recesses exceeds 5.0 mm, the range where the innersurface of the recesses contacts the flow of air will be excessive and,in addition to the air resistance tending to increase, the originalrubber volume in the region including the recesses will increase, whichwill lead to an increase in tire weight. According to this pneumatictire, the inner surface of the recesses appropriately contacts the airand, therefore, the flow of air can be appropriately made turbulent. Asa result, a prominent effect of reducing the air resistance of theentire tire can be obtained.

With the pneumatic tire of the present technology, the recesses aredisposed so that a volume progressively varies in a tire radialdirection.

The rotation speed of the tire side portion becomes relatively fast withproximity to the outer side in the tire radial direction and, therefore,the volume of the recesses in the side closer to the outer side in thetire radial direction is made smaller. As a result, effects on the innerside in the tire radial direction where the rotation speed is relativelyslow are enhanced and equal effects in the tire radial direction can beexpected. On the other hand, if the volume of the recesses is configuredto progressively increase toward the outer side in the tire radialdirection, the effects at the outer side in the tire radial directionwhere the rotation speed is relatively fast are further enhanced andoverall effects as a tire can be enhanced. These configurations can beselected as necessary based on the profile form of the tire.

With the pneumatic tire of the present technology, the protrusions areformed such that a cross-sectional area varies so as to progressivelydecrease toward the outer side in the tire radial direction.

Because the rotation speed of the tire side portion becomes relativelyfast with proximity to the outer side in the tire radial direction, theair resistance can be reduced and aerodynamic performance can beenhanced by reducing the cross-sectional area of the protrusions thatare on the side closer to the outer side in the tire radial direction.

With the pneumatic tire according to the present technology, air flowaround a tire can be further improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a meridian cross-sectional view of a pneumatic tire accordingto an embodiment of the present technology.

FIG. 2 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from a tire widthdirection.

FIG. 3 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 4 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 5 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 6 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 7 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 8 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 9 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 10 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 11 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 12 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 13 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 14 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 15 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 16 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 17 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 18 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 19 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 20 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 21 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 22 is a cross-sectional view of a protrusion.

FIG. 23 is a cross-sectional view of a protrusion.

FIG. 24 is a partial perspective view of the pneumatic tire according tothe embodiment of the present technology, viewed from the tire widthdirection.

FIG. 25 is a meridian cross-sectional view of the pneumatic tireaccording to the embodiment of the present technology.

FIGS. 26a-26c include a table showing results of performance testing ofpneumatic tires according to examples of the present technology.

DETAILED DESCRIPTION

An embodiment of the present technology is described below in detailbased on the drawings. However, the present technology is not limited tothis embodiment. The constituents of the embodiment include constituentsthat can be easily replaced by those skilled in the art and constituentssubstantially same as the constituents of the embodiment. Furthermore, aplurality of modified examples that are described in the embodiment canbe freely combined within a scope of obviousness for a person skilled inthe art.

FIG. 1 is a meridian cross-sectional view of a pneumatic tire accordingto this embodiment. In the following description, “tire radialdirection” refers to a direction orthogonal to the rotational axis (notshown) of the pneumatic tire 1; “inner side in the tire radialdirection” refers to the side facing the rotational axis in the tireradial direction; and “outer side in the tire radial direction” refersto the side distanced from the rotational axis in the tire radialdirection. “Tire circumferential direction” refers to a circumferentialdirection with the rotational axis as a center axis. Additionally, “tirewidth direction” refers to the direction parallel to the rotationalaxis; “inner side in the tire width direction” refers to the side facinga tire equatorial plane CL (tire equator line) in the tire widthdirection; and “outer side in the tire width direction” refers to theside distanced from the tire equatorial plane CL in the tire widthdirection. “Tire equatorial plane CL” refers to a plane that isorthogonal to the rotational axis of the pneumatic tire 1 and thatpasses through a center of a tire width of the pneumatic tire 1. Thetire width is a width in the tire width direction between constituentslocated to the outside in the tire width direction, or in other words,the distance between the constituents that are most distant in the tirewidth direction from the tire equatorial plane CL. “Tire equator line”refers to a line along the tire circumferential direction of thepneumatic tire 1 that lies on the tire equatorial plane CL. In thisembodiment, “tire equator line” is given the same “CL” reference symbolas that used for the tire equatorial plane.

As illustrated in FIG. 1, the pneumatic tire 1 of this embodimentincludes a tread portion 2, shoulder portions 3 on both sides of thetread portion 2, and a side wall portion 4 and a bead portion 5continuing sequentially from each of the shoulder portions 3.Additionally, the pneumatic tire 1 includes a carcass layer 6, a beltlayer 7, and a belt reinforcing layer 8.

The tread portion 2 is formed from a rubber material (tread rubber), isexposed on the outermost side in the tire radial direction of thepneumatic tire 1, and a surface thereof constitutes a profile of thepneumatic tire 1. A tread surface 21 is formed on a peripheral surfaceof the tread portion 2 or, rather, on a road contact surface thatcontacts a road surface when traveling. The tread surface 21 extendsalong the tire circumferential direction, and a plurality (four in thisembodiment) of main grooves 22 that are straight main grooves parallelwith the tire equator line CL are provided in the tread surface 21.Moreover, a plurality of rib-like land portions 23 extending along thetire circumferential direction and parallel with the tire equator lineCL is formed in the tread surface 21 by the plurality of main grooves22. Additionally, while not explicitly illustrated in the drawings, luggrooves that intersect with the main grooves 22 in each of the landportions 23 are provided in the tread surface 21. The land portions 23are plurally divided in the tire circumferential direction by the luggrooves. Additionally, the lug grooves are formed so as to open to anoutermost side in the tire width direction of the tread portion 2, thatis, the outer side in the tire width direction. Note that the luggrooves may have a form that communicates with the main grooves 22 ormay have a form that does not communicate with the main grooves 22.

The shoulder portions 3 are locations on both outer sides in the tirewidth direction of the tread portion 2. Additionally, the side wallportions 4 are exposed at an outermost side in the tire width directionof the pneumatic tire 1. The bead portions 5 include a bead core 51 anda bead filler 52. The bead core 51 is formed by winding a steel wire(bead wire) in a ring-like manner. The bead filler 52 is a rubbermaterial that is disposed in space formed by ends of the carcass layer 6in the tire width direction being folded up at a position of the beadcore 51.

The ends of the carcass layer 6 in the tire width direction are foldedover the pair of bead cores 51 from the inner side in the tire widthdirection to the outer side in the tire width direction, and the carcasslayer 6 is stretched in a toroidal shape in the tire circumferentialdirection to form the framework of the tire. The carcass layer 6 isconstituted by a plurality of carcass cords (not illustrated) juxtaposedin the tire circumferential direction along the tire meridian directionhaving a given angle with respect to the tire circumferential direction,and covered by a coating rubber. The carcass cords are formed fromorganic fibers (e.g. polyester, rayon, nylon, or the like). At least onelayer of this carcass layer 6 is provided.

The belt layer 7 has a multi-layer structure where at least two layers(belts 71 and 72) are stacked; is disposed on an outer side in the tireradial direction that is the periphery of the carcass layer 6, in thetread portion 2; and covers the carcass layer 6 in the tirecircumferential direction. The belts 71 and 72 are constituted by aplurality of cords (not illustrated) juxtaposed at a predetermined anglewith respect to the tire circumferential direction (e.g. from 20 degreesto 30 degrees), and covered by a coating rubber. The cords are formedfrom steel or organic fibers (e.g. polyester, rayon, nylon, or thelike). Moreover, the overlapping belts 71 and 72 are disposed so thatthe cords thereof mutually cross.

The belt reinforcing layer 8 is disposed on the outer side in the tireradial direction that is the periphery of the belt layer 7, and coversthe belt layer 7 in the tire circumferential direction. The beltreinforcing layer 8 is constituted by a plurality of cords (notillustrated), juxtaposed in the tire width direction and substantiallyparallel (±5 degrees) to the tire circumferential direction, which arecovered by a coating rubber. The cords are formed from steel or organicfibers (e.g. polyester, rayon, nylon, or the like). The belt reinforcinglayer 8 illustrated in FIG. 1 is disposed so as to cover end portions inthe tire width direction of the belt layer 7. The configuration of thebelt reinforcing layer 8 is not limited to that described above. Whilenot explicitly illustrated in the drawings, a configuration may be usedwhere the belt reinforcing layer 8 is disposed so as to cover anentirety of the belt layer 7. Alternatively, for example, aconfiguration may be used where the belt reinforcing layer 8 has tworeinforcing layers, where the belt reinforcing layer 8 is formed so thatthe reinforcing layer on the inner side in the tire radial direction islonger in the tire width direction than the belt layer 7 and disposed soas to cover the entirety of the belt layer 7, and the reinforcing layeron the outer side in the tire radial direction is disposed so as only tocover the end portions in the tire width direction of the belt layer 7.Alternatively, for example, a configuration may be used where the beltreinforcing layer 8 has two reinforcing layers, where each of thereinforcing layers is disposed so as only to cover the end portions inthe tire width direction of the belt layer 7. In other words, the beltreinforcing layer 8 overlaps with at least the end portions in the tirewidth direction of the belt layer 7. Additionally, the belt reinforcinglayer 8 is provided by winding band-like (e.g. with a width of 10 mm)strip material in the tire circumferential direction.

FIGS. 2 to 21 are partial perspective views of the pneumatic tireaccording to the embodiment of the present technology, viewed from thetire width direction. As illustrated in FIGS. 2 to 21, with thepneumatic tire 1 configured as described above, a plurality ofprotrusions 9 protruding outward of the tire from a surface of a tireside portion S is provided on at least one tire side portion S, and aplurality of recesses 10 recessed inward of the tire from the surface ofthe tire side portion S is provided in the tire side portion S.

Here, the “tire side portion S” refers to, in FIG. 1, the outer side inthe tire width direction from a ground contact edge T of the treadportion 2 or, in other words, a surface that uniformly continues in arange of the outer side in the tire radial direction from a rim checkline L. Additionally, the “ground contact edge T” refers to bothoutermost edges in the tire width direction of a region in which thetread surface 21 of the tread portion 2 of the pneumatic tire 1 contactsthe road surface when the pneumatic tire 1 is assembled on a regular rimand filled with regular inner pressure and 70% of a regular load isapplied, and the ground contact edge T continues in the tirecircumferential direction. Moreover, the “rim check line L” refers to aline used to confirm whether the tire has been assembled on the rimcorrectly and, typically, is an annular convex line closer to the outerside in the tire radial direction than a rim flange and continues in thetire circumferential direction along a portion adjacent to the rimflange on a front side surface of the bead portions 5.

Here, “regular rim” refers to a “standard rim” defined by the JapanAutomobile Tyre Manufacturers Association Inc. (JATMA), a “design rim”defined by the Tire and Rim Association, Inc. (TRA), or a “measuringrim” defined by the European Tyre and Rim Technical Organisation(ETRTO). “Regular inner pressure” refers to “maximum air pressure”stipulated by JATMA, a maximum value in “tire load limits at variouscold inflation pressures” defined by TRA, and “inflation pressures”stipulated by ETRTO. Note that “regular load” refers to “maximum loadcapacity” stipulated by JATMA, a maximum value in “tire load limits atvarious cold inflation pressures” defined by TRA, and “load capacity”stipulated by ETRTO.

As illustrated in FIGS. 2 to 18, with the pneumatic tire 1 of thisembodiment, the tire side portion S is divided into at least two regionsin the tire radial direction, namely, a region F including theprotrusions 9 and a region D including the recesses 10. Additionally,the region D including the recesses 10 is provided in an outermost sidein the tire radial direction and the region F including the protrusions9 is provided inward in the tire radial direction of the region Dincluding the recesses 10.

The protrusions 9 are, for example, as illustrated in FIGS. 2 to 17,formed as convexities having a longitudinal shape in the tire radialdirection that are formed from a rubber material (may be the rubbermaterial forming the tire side portion S or a rubber material differentfrom said rubber material) in a range of the tire side portion S, and aplurality of the protrusions 9 is disposed in the tire circumferentialdirection at a pitch. As illustrated in FIGS. 2 to 17, the region Fincluding the protrusions 9 is a region between an imaginary lineconnecting ends on the outermost side in the tire radial direction ofthe protrusions 9 that are adjacent in the tire circumferentialdirection, and an imaginary line connecting ends on the innermost sidein the tire radial direction of the protrusions 9 that are adjacent inthe tire circumferential direction.

As illustrated in FIGS. 2 to 4 and FIGS. 6 to 14, the protrusions 9 maybe disposed equidistantly in the tire circumferential direction or, asillustrated in FIG. 5 and FIGS. 15 to 17, a plurality of the protrusions9 (two in the drawings) that are adjacent at a predetermined pitch inthe tire circumferential direction may be configured as a group and thisgroup of protrusions 9 may be disposed equidistantly in the tirecircumferential direction.

Additionally, as illustrated in FIGS. 2 to 14, the protrusions 9 may beformed so as to have a linear form along the tire radial direction or,as illustrated in FIG. 15, may be formed so as to have a linear formthat is inclined with respect to the tire radial direction.Alternatively, as illustrated in FIG. 16, the protrusions 9 may beformed so as to bend or, as illustrated in FIG. 17, may be formed so asto curve.

Additionally, as illustrated in FIGS. 10 to 17, the protrusions 9 may bedisposed in the tire circumferential direction so as to have mutuallydiffering lengths.

As illustrated in FIGS. 2 to 10 and FIG. 13, a shape of the protrusions9 when viewed from the tire width direction may be rectangular.Alternatively, as illustrated in FIG. 11, the end portions of theprotrusions 9 may be arc-shaped; as illustrated in FIG. 12, the endportions may be pointed; or as illustrated in FIG. 14, the end portionsmay be triangular. Additionally, as illustrated in FIG. 14, a width ofthe protrusions 9 (a dimension that crosses a longitudinal direction ofthe protrusions 9) may be formed so as to vary in the longitudinaldirection.

Moreover, a cross-sectional shape orthogonal to the longitudinaldirection of the protrusions 9 is formed so as to be semicircular,semi-elliptical, semi-oval, triangular, rectangular, or trapezoidal or,at least a portion of the cross-sectional shape has an arc. Here,“orthogonal to the longitudinal direction of the protrusions 9” means adirection that is orthogonal to the extending direction of theprotrusions 9, and, in the case that the protrusions 9 are formed so asto curve, means a direction orthogonal to a line tangent to the curvedportion.

Note that while not explicitly illustrated in the drawings, theprotrusions 9 may be divided plurally in the longitudinal direction. Incases where the protrusions 9 are divided, another protrusion 9 lined upin the tire circumferential direction thereof may be disposed so as tooverlap, in the tire circumferential direction, a division of aprotrusion 9 adjacent in the tire circumferential direction.

An opening shape of the recesses 10 opening at the surface of the tireside portion S may be circular, elliptical, oval, polygonal, or the like(in FIGS. 2 to 17, circular opening shapes are illustrated). Moreover, across-sectional shape of the recesses 10 may be semicircular,semi-elliptical, semi-oval, rounded cone shaped, rectangular, or thelike. As illustrated in FIGS. 2 to 17, the region D including therecesses 10 is a region between an imaginary line connecting edges ofadjacent recesses 10 that are closest to the outermost side in the tireradial direction, and an imaginary line connecting edges of adjacentrecesses 10 that are closest to the innermost side in the tire radialdirection.

As illustrated in FIGS. 2 to 5, the recesses 10 may be disposedequidistantly in the tire circumferential direction and the tire radialdirection and, as illustrated in FIG. 3, the recesses 10 may be disposedalong the tire radial direction along which the protrusions 9 aredisposed. Additionally, as illustrated in FIG. 6, the recesses 10 may bedisposed so as to have a void in a portion equidistantly disposed in thetire circumferential direction and the tire radial direction. Moreover,as illustrated in FIG. 7, the recesses 10 may be disposed so as to havea void in a portion disposed along the tire radial direction along whichthe protrusions 9 are disposed. Furthermore, as illustrated in FIGS. 8and 9, the recesses 10 may be disposed having different sizes.Additionally, as illustrated in FIGS. 10 to 17, the recesses 10 may bedisposed in peaks and valleys so as to correspond to the protrusions 9that are disposed in the tire circumferential direction so as to havemutually differing lengths. Moreover, while not explicitly illustratedin the drawings, the recesses 10 may be disposed in a staggered manner,or may be disposed in a rectangular- or triangular-based manner.

As described above, the tire side portion S of this embodiment isdivided into at least two regions in the tire radial direction, namely,the region D including the recesses 10 and the region F including theprotrusions 9. The region D including the recesses 10 is provided in theoutermost side in the tire radial direction and the region F includingthe protrusions 9 is provided inward in the tire radial direction of theregion D including the recesses 10 (see FIG. 18). Additionally, asillustrated in FIG. 19, with the region D including the recesses 10 andthe region F including the protrusions 9, the region D including therecesses 10 may be provided in the outermost side in the tire radialdirection and the region F including the protrusions 9 may be providedon the innermost side in the tire radial direction, and a region wherethe protrusions 9 and the recesses 10 are not provided may be providedbetween the region F and the region D in the tire radial direction.Additionally, as illustrated in FIG. 20, with the region D including therecesses 10 and the region F including the protrusions 9, the region Dincluding the recesses 10 may be provided in the outermost side in thetire radial direction and the region F including the protrusions 9 maybe provided on the innermost side in the tire radial direction, andanother region D and another region F may be provided between the regionF and the region D in the tire radial direction. Moreover, asillustrated in FIG. 21, a boundary between the region D including therecesses 10 and the region F including the protrusions 9 may be providedso as to be wavelike in the tire circumferential direction or, asillustrated in FIGS. 10 to 12 and FIGS. 14 to 17, the boundary may beprovided so as to be saw-toothed (zigzagged) in the tire circumferentialdirection. Furthermore, as illustrated in FIG. 13, the boundary betweenthe region D including the recesses 10 and the region F including theprotrusions 9 may be provided so that the region D and the region Foverlap.

In the tire side portions S on both sides in the tire width direction,the protrusions 9 and the recesses 10 may be provided with identicalarrangements or may be provided with differing arrangements.Additionally, in the tire side portions S on both sides in the tirewidth direction, the region D including the recesses 10 and the region Fincluding the protrusions 9 may be provided with identical arrangementsor differing arrangements.

Thus, the pneumatic tire 1 of this embodiment includes the plurality ofprotrusions 9 and the plurality of recesses 10 of at least one of thetire side portions S; the region D including the recesses 10 is providedin the outermost side in the tire radial direction; the protrusions 9are formed as convexities having a longitudinal shape in a predetermineddirection; and the region F including the protrusions 9 is providedinward in the tire radial direction of the region D including therecesses 10.

When a vehicle on which the pneumatic tire 1 is mounted is traveling, byproviding the region D including the recesses 10 in the outer side inthe tire radial direction of the tire side portion S where airresistance is prone to be received and rotation speed is relativelyfast, the air will be made turbulent by the recesses 10. Therefore, aturbulent flow boundary layer is generated in the region D including therecesses 10 and the expansion of passing air is suppressed. That is,separation of the flow of air from the shoulder portion 3 (also referredto as the buttress portion), which is a portion on both outer sides ofthe tread portion 2 in the tire width direction and is inclined inwardin the tire radial direction, is suppressed. As a result, a point wherethe flow of air separates can be offset backward and, therefore, the airresistance of the entire tire is reduced and fuel economy is enhanced.On the other hand, when a vehicle on which the pneumatic tire 1 ismounted is traveling, by providing the region F including theprotrusions 9 on the inner side in the tire radial direction of the tireside portion S where the rotation speed is relatively slow, the flow ofair for which separation was suppressed by the recesses 10 is madeturbulent by the protrusions 9. Therefore, a turbulent flow boundarylayer is generated in the region F including the protrusions 9 andexpansion of passing air can be further suppressed. As a result, the airresistance of the vehicle is reduced and the fuel economy is enhanced.Moreover, the flow of air for which separation was suppressed by therecesses 10 is rectified by the protrusions 9 and expelled toward theback of the tire. Therefore, the air resistance of the vehicle can befurther reduced. Particularly, in a vehicle in which the pneumatic tire1 is disposed within a fender, air is expelled backward in the fender bythe protrusions 9 and, therefore, the air resistance of the vehicle isfurther reduced. As described above, with this pneumatic tire 1, it ispossible to further improve the air flow around the tire due to therecesses 10 in the outer side in the tire radial direction and theprotrusions 9 on the inner side in the tire radial direction of the tireside portion S.

As illustrated in FIG. 1, with the pneumatic tire 1 according to thisembodiment, in a state when assembled on a regular rim and inflated toan inner pressure of 5% of a regular inner pressure, the region Dincluding the recesses 10 is preferably a range DH of at least 10% of atire cross-sectional height H outward from a ground contact edge T ofthe tread portion 2 in the tire width direction and inward from theground contact edge T in the tire radial direction; and the region Fincluding the protrusions 9 is preferably a range FH of at least 10% ofthe tire cross-sectional height H outward from the rim check line L inthe tire radial direction.

Here, “tire cross-sectional height H” refers to a height of the tirealong the tire radial direction from an inner edge of the bead portion 5in the tire radial direction (rim base position) to a tread surface 21on the outermost side in the tire radial direction (crown center).

The range DH of at least 10% of a tire cross-sectional height H outwardfrom a ground contact edge T of the tread portion 2 in the tire widthdirection and inward in the tire radial direction from the groundcontact edge T is a portion in the tire side portion S that is mostprone to receiving the air resistance and where the rotation speed isfastest. By configuring this range DH to be the region D including therecesses 10, a prominent effect of reducing the air resistance of theentire tire can be obtained and the fuel economy can be furtherenhanced. On the other hand, the range FH of at least 10% of the tirecross-sectional height H outward from the rim check line L in the tireradial direction is a portion in the tire side portion S where therotation speed is slowest. By configuring this range FH to be the regionF including the protrusions 9, the flow of air for which separation wassuppressed by the recesses 10 can be made more turbulent, a prominenteffect of reducing the air resistance of the vehicle can be obtained,and the fuel economy can be further enhanced. Note that setting maximumvalues of the regions FH and DH to 70% of the tire cross-sectionalheight H is preferable because the effects of the protrusions 9 and therecesses 10 that are obtained will be prominent. Additionally, settingthe regions FH and DH to 50% of the tire cross-sectional height H ismore preferable because the protrusions 9 and the recesses 10 will reachthe position in the tire cross-sectional width where the width issubstantially the greatest, and the effects of the protrusions 9 and therecesses 10 will be divided substantially evenly in the tire radialdirection. When the pneumatic tire 1 is assembled on a regular rim,inflated to a regular inner pressure, and in an unloaded state, the“tire cross-sectional width” is a distance in the tire width directionfound by excluding design and alphanumeric portions from a total tirewidth, i.e. a linear distance in the tire width direction between theside wall portions 4 including all designs or alphanumerics on the sidefaces.

With the pneumatic tire 1 of this embodiment, a longitudinal directiondimension of the protrusions 9 is preferably not less than 5 mm.

If the longitudinal direction dimension of the protrusions 9 is lessthan 5 mm, it will be difficult to obtain the effect of making the airturbulent by the protrusions 9. Therefore, configuring the longitudinaldirection dimension of the protrusions 9 to be not less than 5 mm makesit possible to make the air turbulent and obtain a prominent effect ofreducing the air resistance of the vehicle.

With the pneumatic tire 1 of this embodiment, a protruding height of theprotrusions 9 is preferably not less than 0.5 mm and not more than 10.0mm.

If the height of the protrusions 9 is less than 0.5 mm, a range of theprotrusions 9 that contacts the air will be small and, as a result, itwill be difficult to make the flow of air turbulent and the effect ofreducing the air resistance of the vehicle will decline. Additionally,if the height of the protrusions 9 exceeds 10.0 mm, the range of theprotrusions 9 that contacts the air will be large and, as a result, theflow of air at the back of the protrusions 9 will tend to expand and theeffect of reducing the air resistance of the vehicle will decline. Onthis point, according to the pneumatic tire 1 of this embodiment, theprotrusions 9 appropriately contact the air and, therefore, the flow ofair is made turbulent and the expansion of the air at the back of theprotrusions 9 is reduced. As a result, a prominent effect of reducingthe air resistance of the vehicle can be obtained. Note that the heightof the protrusions 9 is preferably configured to be not less than 1 mmand not more than 5 mm because a more prominent effect of reducing theair resistance of the vehicle will be obtained. Note that the range ofthe height of the protrusions 9 that is not less than 0.5 mm and notmore than 10.0 mm is preferable for pneumatic tires for passenger cars.However, the range is not limited thereto for pneumatic tires havinglarge diameters such as heavy duty pneumatic tires, and the range of theheight may exceed that for passenger cars.

With the pneumatic tire 1 of this embodiment, a longitudinal directionof the protrusions 9 is preferably disposed along the tire radialdirection.

The protrusions 9 formed with the longitudinal shape in the tire radialdirection have many faces facing the air passing around the tire andmake the air more turbulent. Therefore, a prominent effect of reducingthe air resistance of the vehicle can be obtained.

With the pneumatic tire 1 of this embodiment, a cross-sectional shape ofthe protrusions 9 preferably includes a peak and progressively expandstoward a bottom surface side.

That is, the cross-sectional shape of the protrusions 9 that isorthogonal to the longitudinal direction resembles a triangle shape and,thereby, the volume of the protrusions 9 is less compared to that of arectangular cross-section or the like. As a result, the rubber volume ofthe protrusions 9 is reduced and an increase in tire weight issuppressed and, therefore, the fuel economy can be further enhanced.

With the pneumatic tire 1 of this embodiment, the cross-sectional shapeof the protrusions 9 preferably includes at least one arc.

For example, as illustrated in FIG. 22 (a cross-sectional view of aprotrusion), the cross-sectional shape of the protrusions 9 may beformed so as to expand using an arc or, as illustrated in FIG. 23 (across-sectional view of a protrusion), the cross-sectional shape of theprotrusions 9 may be formed so that the arc is recessed. As a result,because the volume of the protrusions 9 is less compared to that of arectangular cross-section or the like, the rubber volume of theprotrusions 9 is reduced and an increase in tire weight is suppressedand, therefore, the fuel economy can be further enhanced.

With the pneumatic tire 1 of this embodiment, a depth of the recesses 10is preferably not less than 0.5 mm and not more than 5.0 mm.

If the depth of the recesses 10 is less than 0.5 mm, a range where aninner surface of the recesses 10 contacts the air will be small and, asa result, it will be difficult to make the flow of air turbulent.Additionally, if the depth of the recesses 10 exceeds 5.0 mm, the rangewhere the inner surface of the recesses 10 contacts the air will beexcessive and, in addition to the air resistance tending to increase,the original rubber volume in the region including the recesses 10 willincrease, which will lead to an increase in tire weight. On this point,according to the pneumatic tire 1 of this embodiment, the inner surfaceof the recesses 10 appropriately contacts the air and, therefore, theflow of air can be appropriately made turbulent. As a result, aprominent effect of reducing the air resistance of the entire tire canbe obtained. Note that the range of the depth of the recesses 10 that isnot less than 0.5 mm and not more than 5.0 mm is preferable forpneumatic tires for passenger cars. However, the range is not limitedthereto for pneumatic tires having large diameters such as heavy dutypneumatic tires, and the range of the depth may exceed that forpassenger cars.

With the pneumatic tire 1 of this embodiment, the recesses 10 arepreferably disposed so that a volume progressively varies in a tireradial direction.

The volume of the recesses 10 varies depending on the depth of therecesses 10 and an area of the openings of the recesses 10. For example,as illustrated in FIG. 24 (a partial perspective view of the pneumatictire according to this embodiment, viewed from the tire widthdirection), by configuring the depth of the recesses 10 to be constantand the area of the openings to vary and progressively decrease towardthe outer side in the tire radial direction, the volumes of the recesses10 can be made so as to progressively decrease toward the outer side inthe tire radial direction. The rotation speed of the tire side portion Sbecomes relatively fast with proximity to the outer side in the tireradial direction and, therefore, the volume of the recesses 10 in theside closer to the outer side in the tire radial direction is madesmaller. As a result, effects on the inner side in the tire radialdirection where the rotation speed is relatively slow are enhanced andequal effects in the tire radial direction can be expected. On the otherhand, while not explicitly illustrated in the drawings, for example, byconfiguring the depth of the recesses 10 to be constant and the area ofthe openings to progressively increase toward the outer side in the tireradial direction, the volume of the recesses 10 progressively increasestowards the outer side in the tire radial direction. As a result, theeffects at the outer side in the tire radial direction where therotation speed is relatively fast are further enhanced and overalleffects as a tire can be enhanced. These configurations can be selectedas necessary based on the profile form of the tire.

Additionally, with the pneumatic tire 1 of this embodiment, theprotrusions 9 are preferably formed such that a cross-sectional areavaries so as to progressively decrease toward the outer side in the tireradial direction.

The cross-sectional area of the protrusions 9 varies depending on thecross-sectional shape (the width of the protrusions 9 or the height ofthe protrusions 9) of the protrusions 9. For example, as illustrated inFIG. 14, by configuring the height of the protrusions 9 to be constantand the width to progressively decrease toward the outer side in thetire radial direction, the cross-sectional area of the protrusions 9will progressively decrease toward the outer side in the tire radialdirection. Because the rotation speed of the tire side portion S becomesrelatively fast with proximity to the outer side in the tire radialdirection, the air resistance can be reduced and aerodynamic performancecan be enhanced by reducing the cross-sectional area of the protrusions9 that are on the side closer to the outer side in the tire radialdirection. Additionally, as illustrated in FIG. 25 (a meridiancross-sectional view of the pneumatic tire according to thisembodiment), by configuring the width of the protrusions 9 to beconstant and the height to progressively decrease toward the outer sidein the tire radial direction, the cross-sectional area of theprotrusions 9 will progressively decrease toward the outer side in thetire radial direction. Therefore, the cross-sectional area of theprotrusions 9 on the side closer to the portion where the rotation speedis relatively fast is reduced and, as a result, the air resistance canbe reduced and aerodynamic performance can be enhanced.

The pneumatic tire 1 described above can be used as a passenger carpneumatic tire and also as a heavy duty or run-flat pneumatic tire. Whenused as a passenger car pneumatic tire, the effects described above canbe obtained. When used as a heavy duty pneumatic tire, particularlyunder heavy loads, deformations of the tire when the tire side portion Sis compressed are further suppressed by the protrusions 9, and increasesin temperature when the tire side portion S is compressed are suppressedby the recesses 10. Therefore, durability is enhanced. Also, when usedas a run-flat pneumatic tire, particularly when punctured, deformationsof the tire when the tire side portion S is compressed are furthersuppressed by the protrusions 9, and increases in temperature when thetire side portion S is compressed are suppressed by the recesses 10.Therefore, durability is enhanced.

EXAMPLES

In the examples, performance testing for fuel economy was performed on aplurality of types of pneumatic tires under different conditions (seeFIGS. 26a-c ).

In this performance testing, a pneumatic tire having a tire size of185/65R15 was assembled on a regular rim and inflated to a regular innerpressure. Then, the pneumatic tire was mounted on a compact front-wheeldrive vehicle having an engine displacement of 1,500 cc+motor assistdrive.

Fuel economy performance testing: Fuel economy was measured for a casewhere the test vehicle described above was driven 50 laps on a 2 km(total length) test course at a speed of 100 km/h. Based on themeasurement results, the fuel economy improvement rates were indexedwith the index score of the pneumatic tire of the Conventional Example(100) being a reference. Greater index scores indicate enhanced fueleconomy improvement rates.

In FIGS. 26a-c , the pneumatic tire of the Conventional Example did notinclude the protrusions and the recesses of the tire side portions ofboth sides. Additionally, the pneumatic tire of Comparative Example 1included protrusions on an inner side region in the tire radialdirection of the tire side portions of both sides (intermediate portionbetween the rim check line and the position where the tirecross-sectional width is greatest), and did not include the recesses.The pneumatic tire of Comparative Example 2 included recesses in anouter side region in the tire radial direction of the tire side portionsof both sides (intermediate portion between the ground contact edge andthe position where the tire cross-sectional width is greatest), and didnot include the protrusions. The pneumatic tire of Comparative Example 3included the protrusions on an outer side region in the tire radialdirection of the tire side portions of both sides (intermediate portionbetween the ground contact edge and the position where the tirecross-sectional width is greatest) and on the inner side region in thetire radial direction of the tire side portions of both sides(intermediate portion between the rim check line and the position wherethe tire cross-sectional width is greatest). The pneumatic tire ofComparative Example 4 included the recesses in an outer side region inthe tire radial direction of the tire side portions of both sides(intermediate portion between the ground contact edge and the positionwhere the tire cross-sectional width is greatest) and in the inner sideregion in the tire radial direction of the tire side portions of bothsides (intermediate portion between the rim check line and the positionwhere the tire cross-sectional width is greatest). Note that when theprotrusions were included, the length along the tire radial directionwas uniform and the protrusions were disposed equidistantly in the tirecircumferential direction. When the recesses were included, the recesseswere juxtaposed along the tire radial direction and equidistantlydisposed in the tire circumferential direction.

On the other hand, in FIGS. 26a-c , the pneumatic tires of WorkingExamples 1 to 10 included the recesses in the outer side in the tireradial direction of the tire side portions of both sides, and includedthe protrusions on the inner side in the tire radial direction of thetire side portions of both sides. Note that the recesses were juxtaposedalong the tire radial direction and equidistantly disposed in the tirecircumferential direction, and the protrusions were equidistantlydisposed in the tire circumferential direction, inward in the tireradial direction of the recesses and with a uniform length along thetire radial direction (see FIG. 2). The pneumatic tire of WorkingExample 1 included the recesses in an outer side region in the tireradial direction of the tire side portions of both sides (intermediateportion between the ground contact edge and the position where the tirecross-sectional width is greatest), and included protrusions on theinner side region in the tire radial direction of the tire side portionsof both sides (intermediate portion between the rim check line and theposition where the tire cross-sectional width is greatest).Additionally, the pneumatic tires of Working Examples 2 to 10, in astate when assembled on a regular rim and inflated to an inner pressureof 5% of a regular inner pressure, the recesses were provided in theinner side region in the tire radial direction of the tire side portionsof both sides (range of 10% of the tire cross-sectional height inwardfrom the ground contact edge in the tire radial direction), and theprotrusions were provided on the inner side region in the tire radialdirection of the tire side portions of both sides (range of 10% of thetire cross-sectional height outward from the rim check line in the tireradial direction). With the pneumatic tires of Working Examples 3 to 10,the longitudinal direction dimension of the protrusions was furtherconfigured to the stipulated value. With the pneumatic tires of WorkingExamples 4 to 10, the protruding height of the protrusions and the depthof the recesses were further configured to the stipulated values. Withthe pneumatic tire of Working Example 6, the cross-sectional shape ofthe protrusions was configured to be triangular (isosceles triangular).With the pneumatic tires of Working Examples 7 to 10, thecross-sectional shape of the protrusions was formed to be triangular(isosceles triangular) in which two sides were formed as recessed arcs(see FIG. 23). With the pneumatic tire of Working Example 8, the volumeof the recesses varied in the tire radial direction. The recesses havinga circular opening shape were configured so that the opening radius wasin a range from 0.3 to 2 mm and the depth was in a range from 3 to 4 mm.The recesses with the smallest volume were disposed on the outer side inthe tire radial direction and the volume varied so as to progressivelyincrease toward the inner side in the tire radial direction (see FIG.24). With the pneumatic tire of Working Example 9, the volume of therecesses varies in the tire radial direction. The recesses having acircular opening shape are configured so that the opening radius is in arange from 0.3 to 2 mm and the depth is in a range from 3 to 4 mm. Therecesses with the smallest volume were disposed on the inner side in thetire radial direction and the volume varied so as to progressivelyincrease toward the outer side in the tire radial direction. With thepneumatic tire of Working Example 10, the cross-sectional area of theprotrusions varies in the tire radial direction. The height of theprotrusions was in a range from 1 to 8 mm. The cross-sectional area atthe inner side in the tire radial direction was greatest and thecross-sectional area varied so as to progressively decrease toward theouter side in the tire radial direction (see FIG. 25).

As shown in the evaluation results of FIGS. 26a-c , it is clear that thefuel economy was enhanced with the pneumatic tires of Working Examples 1to 10.

What is claimed is:
 1. A pneumatic tire comprising: a tread portionincluding a pair of tread ground contact edges; a pair of rim checklines; and a pair of tire side portions each forming an outer surface ina tire width direction provided on the outer side in the tire widthdirection of a respective tread ground contact edge and uniformlycontinuing to a respective rim check line; at least one of the pair oftire side portions having a plurality of recesses recessed inward of thetire from a surface of the tire side portion and a plurality ofprotrusions protruding outward of the tire from the surface of the tireside portion; wherein a region including the recesses is provided in anoutermost side in a tire radial direction, the protrusions are formed asconvexities having a longitudinal shape in a predetermined direction,and a region including the protrusions is formed inward in the tireradial direction of the region including the recesses, the predetermineddirection is the tire radial direction, the protrusions are discrete ina tire circumferential direction, the region including the recesses is aregion between a first imaginary line connecting edges of adjacentradially outermost recesses and a second imaginary line connecting edgesof adjacent radially innermost recesses, a region including theprotrusions is a region between a third imaginary line connecting outerends on an outermost side in the tire radial direction of theprotrusions that are adjacent in a tire circumferential direction and afourth imaginary line connecting inner ends on an innermost side in thetire radial direction of the protrusions that are adjacent in the tirecircumferential direction, the region in eluding the protrusions isentirely radially inward of the second imaginary line, the regionincluding the recesses is entirely radially outward of the thirdimaginary line, the second imaginary line and the third imaginary lineextend in a wave or zigzag shape in the tire circumferential direction,and overlap with each other in the tire radial direction, and the secondimaginary line is radially outward of the third imaginary line at eachcircumferential positions.
 2. The pneumatic tire according to claim 1,wherein in a state when assembled on a regular rim and inflated to aninner pressure of 5% of a regular inner pressure, the region includingthe recesses is a range of at least 10% of a tire cross-sectional heightoutward from a ground contact edge of a tread portion in a tire widthdirection and inward from the ground contact edge in the tire radialdirection; and the region including the protrusions is a range of atleast 10% of the tire cross-sectional height outward from a rim checkline in the tire radial direction.
 3. The pneumatic tire according toclaim 1, wherein a longitudinal direction dimension of the protrusionsis not less than 5 mm.
 4. The pneumatic tire according to claim 1,wherein a protruding height of the protrusions is not less than 0.5 mmand not more than 10.0 mm.
 5. The pneumatic tire according to claim 1,wherein a cross-sectional shape of the protrusions comprises a peak andprogressively expands toward a bottom surface side.
 6. The pneumatictire according to claim 1, wherein a cross-sectional shape of theprotrusions comprises at least one arc.
 7. The pneumatic the accordingto claim 1, wherein a depth of the recesses is not less than 0.5 mm andnot more than 5.0 mm.
 8. The pneumatic tire according to claim 1,wherein the recesses are disposed so that a volume progressively variesin the tire radial direction.
 9. The pneumatic tire according to claim1, wherein the protrusions are formed such that a cross-sectional areain a cross-sectional view of the tire circumferential direction variesso as to progressively decrease from a maximum height toward the outerside in the tire radial direction.
 10. The pneumatic tire according toclaim 1, wherein in a state where the tire is assembled on a regular rimand inflated to an inner pressure of 5% of a regular inner pressure,when a range of at least 10% of a tire cross-sectional height outwardfrom a ground contact edge of a tread portion in the tire widthdirection and inward in the tire radial direction from the groundcontact edge is defined as DH, and another range of at least 10% of atire cross-sectional height outward from a rim check line in the tireradial direction is defined as FH, and wherein maximum values of theregions FH and DH are respectively not more than 70% of the tirecross-sectional height.
 11. The pneumatic tire according to claim 1,wherein in a state where the tire is assembled on a regular rim andinflated to an inner pressure of 5% of a regular inner pressure, when arange of at least 10% of a tire cross-sectional height outward from aground contact edge of a tread portion in the tire width direction andinward in the tire radial direction from the ground contact edge isdefined as DH, and another range of at least 10% of a tirecross-sectional height outward from a rim check line in the tire radialdirection is defined as FH, and wherein maximum values of the regions FHand DH are respectively not more than 50% of the tire cross-sectionalheight.
 12. The pneumatic tire according to claim 1, wherein in a statewhen assembled on a regular rim and inflated to an inner pressure of 5%of a regular inner pressure, the region including the recesses is arange of at least 10% of a tire cross-sectional height outward from aground contact edge of a tread portion in a tire width direction andinward from the ground contact edge in the tire radial direction. 13.The pneumatic tire according to claim 1, wherein in a state whenassembled on a regular rim and inflated to an inner pressure of 5% of aregular inner pressure, and the region including the protrusions is arange of at least 10% of the tire cross-sectional height outward from arim check line in the tire radial direction.
 14. The pneumatic tireaccording to claim 1, wherein a longitudinal direction dimension of theprotrusions is not less than 5 mm and having a protruding height of notless than 0.5 mm and not more than 10.0 mm.
 15. The pneumatic tireaccording to claim 1, wherein the recesses are disposed so that a volumeprogressively varies in the tire radial direction and the protrusionsare formed such that a cross-sectional area in a cross-sectional view ofthe tire circumferential direction varies so as to progressivelydecrease from a maximum height toward the outer side in the tire radialdirection.
 16. The pneumatic tire according to claim 1, wherein: theregion including the recesses does not include the protrusions; and theregion including the protrusions does not include the recesses.
 17. Thepneumatic tire according to claim 1, wherein: the region including therecesses includes all of the recesses; and the region including theprotrusions includes all of the protrusions.
 18. The pneumatic tireaccording to claim 1, wherein the second imaginary line does not crossthe third imaginary line.
 19. The pneumatic tire according to claim 1,wherein the second imaginary line crosses the third imaginary line. 20.The pneumatic tire according to claim 1, wherein the region includingthe recesses is a range of at least 10% of a tire cross-sectional heightH outward from a ground contact edge in the tire width direction. 21.The pneumatic tire according to claim 1, wherein the region includingthe protrusions is a range of at least 10% of the tire cross-sectionalheight outward from the rim check line in the tire radial direction. 22.The pneumatic tire according to claim 1, wherein a depth of the recessesto be constant and the area of the openings to vary and progressivelydecrease toward the outer side in the tire radial direction.